The central venous catheterization (central line placement) is the common procedure performed in the intensive care unit. This procedure is performed by percutaneous puncture of so called 'the central vein' and than advancement of the catheter over the guidewire (Seldinger technique). The tip of the catheter is left in the superior vena cava in the vicinity of the right atrium of the heart. Central veins are large veins in the human body passing the blood into the heart.

Typical, clinical indications for the central line placement in the intensive care unit are hemodynamic monitoring, volume monitoring, administration of medications, long-term total parenteral nutrition, access for renal replacement therapy, difficult peripheral catheterization.

There are two methods of the central venous catheterization in terms of visualization. First and older is the blind technique. The operator is locating the anatomical landmarks and then performing the entire procedure blindly by percutaneous puncture. This is called the landmark technique. Second and new is the ultrasound-guided technique. The operator is locating the vein using ultrasonography and then performing the entire procedure under ultrasonographic visualization. The real time ultrasound-guided central venous catheterization became the standard of care in recent years mainly because of safety issues (is regarded as safer than landmark technique)

The catheterization of the axillary vein is not popular procedure in daily clinical practice. But it can be reasonable and safe alternative to others, typically performed central venous catheterizations like the internal jugular vein and the subclavian vein catheterizations.

The main intention of this study is to assess usefulness and safety of the real time ultrasound guided axillary vein catheterization in mechanically ventilated patients admitted to the intensive care unit.

Inclusion Criteria:

• mechanically ventilated intensive care patients with clinical indications for central venous line placement

Exclusion Criteria:

• trauma and hematoma at the catheterization site
• history of multiple central venous catheterizations (three or more)
• chest wall deformities
• major blood coagulation disorders
• history of thoracic surgery
• anatomical abnormalities at the catheterization site
• infection at the catheterization site
• age less than 18 years
• lack of patients or closest relatives consent